The present invention relates to a method and apparatus for cleaning the internal portions of internal combustion engines, particularly those of automotive vehicles including both gasoline powered and diesel powered vehicles.
It is well know that the operating components of internal engines do collect debris and residue which impairs engine performance. The lubricant which reduces friction in the moving engine parts eventually becomes contaminated with sludge, tar and other chemical contaminants which are produced during the operation of the engine and which are entrained in the lubricant. Also, small particulate of metal do become worn away from the operating parts of the engine and are carried in the lubricant. These small, metal particles can damage engine components that operate at high speeds and temperatures. While regular lubricant changes are absolutely necessary to the continued operation of an internal combustion engine, engine components including valves, seals and other operating members do collect contaminants even if the lubricant is changed frequently. These contaminants reduce engine performance.
Various prior systems have existed for cleaning the interior, operating components of internal combustion engines. These conventional systems typically employ a cleaning fluid which is maintained in a reservoir. The reservoir is connected to a pump. The engine cleaning system is provided with an inlet supply line leading from the pump and connected to one of the crankcase openings with which the internal combustion is equipped.
Virtually all internal combustion engines have an opening which is adapted to receive a removable oil filter cartridge, and an oil pan drain plug opening. When the engine is to be cleaned the oil filter is removed, and the inlet supply line leading from the cleaning fluid pump is typically connected to the oil filter opening. Also the crank case drain plug is removed and a cleaning fluid withdrawal line is connected to the drain plug opening in the crankcase pan. The supply line and withdrawal line are typically supplied with adapters so as to minimize leakage of cleaning fluid entering and leaving the engine block. Once the cleaning fluid has been circulated through the engine block, it is returned by the pump to the reservoir. Typical conventional internal combustion engine cleaning systems of this type are described, for example, in U.S. Pat. Nos. 1,549,952; 2,525,978; 3,431,145; 3,489,245; 4,964,373; and 5,063,896.
In the conventional engine cleaning systems the cleaning liquid employed is flushed through the engine block of an internal combustion engine in a single pass, filtered and returned to the reservoir. By passing the cleaning liquid through filters, the finest of which is a 3 micron filter, harmful particulate matter can be removed from the cleaning liquid, so that the cleaning liquid may be used to clean as many as forty internal combustion engines before requiring replacement.
If the cleaning fluid is utilized to clean gasoline powered internal combustion engines it will largely retain its characteristic color and will only gradually become darker as it is utilized to clean up to a maximum of forty such engines. However, if the cleaning fluid is utilized to clean a diesel powered engine, it will immediately become blackened in color, even though harmful particulate matter has been removed by the filter. This strong discoloration is due to differences in the nature of combustion deposits produced in diesel powered engines as contrasted with those produced in gasoline powered engines. The cleaning fluid is stained black upon first being used to clean a diesel powered internal combustion engine, even if the cleaning fluid has not previously been used to clean any other engine. Thus, although the cleaning fluid may be reused for the balance of its useful life of cleaning up to forty engines, the first time it is utilized to clean a diesel powered combustion engine, it becomes black, and stays black for the rest of its useful life.
This feature presents a problem when the cleaning fluid is utilized to clean a gasoline powered internal combustion engine after having once been used to clean a diesel powered engine. The filter housings through which the cleaning fluid passes as it is withdrawn from the engine are typically transparent, so that the cleaning fluid withdrawn from the engine during cleaning is visible as it returns to a reservoir for recovery.
The owners of the vehicles having engines to be cleaning are often curious about the cleaning process and are frequently present and observe the engine cleaning process while it is carried out. The owners of vehicles having gasoline powered engines invariably notice the black color of cleaning fluid which has previously been employed to clean diesel powered internal combustion engines as it is subsequently used to clean their engine. These owners of gasoline powered vehicles assume that such cleaning fluid is so contaminated that it is unsuitable for use in the engines of their vehicles. Consequently, the owners of vehicles employing gasoline driven internal combustion engines often choose not to have their engines cleaned again with cleaning fluid since they become convinced that the cleaning fluid is too dirty to effectively clean their engines.
Another problem with conventional internal combustion engine cleaning systems is that whether or not the cleaning fluid is employed to clean diesel powered engines, it will become discolored somewhat even after it has been used for only a few engine cleanings and still has a very significant portion of its useful life left. Consequently, with the exception of the first few cleanings, the cleaning fluid will always emerge from the internal combustion engine with a certain amount of blackness in color. Automotive owners observing the discolored cleaning fluid being withdrawn from their vehicle engines during the final moments of the cleaning process assume that because the cleaning fluid is still discolored, their engines have not been fully cleaned. They thereupon question the effectiveness and value of the cleaning process. This results in a disinclination to return for subsequent engine cleanings.